1 //===- llvm/Pass.h - Base class for Passes ----------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines a base class that indicates that a specified class is a
11 // transformation pass implementation.
13 // Passes are designed this way so that it is possible to run passes in a cache
14 // and organizationally optimal order without having to specify it at the front
15 // end. This allows arbitrary passes to be strung together and have them
16 // executed as effeciently as possible.
18 // Passes should extend one of the classes below, depending on the guarantees
19 // that it can make about what will be modified as it is run. For example, most
20 // global optimizations should derive from FunctionPass, because they do not add
21 // or delete functions, they operate on the internals of the function.
23 // Note that this file #includes PassSupport.h and PassAnalysisSupport.h (at the
24 // bottom), so the APIs exposed by these files are also automatically available
25 // to all users of this file.
27 //===----------------------------------------------------------------------===//
32 #include "llvm/System/DataTypes.h"
48 class AnalysisResolver;
53 // AnalysisID - Use the PassInfo to identify a pass...
54 typedef const PassInfo* AnalysisID;
56 /// Different types of internal pass managers. External pass managers
57 /// (PassManager and FunctionPassManager) are not represented here.
58 /// Ordering of pass manager types is important here.
59 enum PassManagerType {
61 PMT_ModulePassManager = 1, ///< MPPassManager
62 PMT_CallGraphPassManager, ///< CGPassManager
63 PMT_FunctionPassManager, ///< FPPassManager
64 PMT_LoopPassManager, ///< LPPassManager
65 PMT_BasicBlockPassManager, ///< BBPassManager
69 // Different types of passes.
79 //===----------------------------------------------------------------------===//
80 /// Pass interface - Implemented by all 'passes'. Subclass this if you are an
81 /// interprocedural optimization or you do not fit into any of the more
82 /// constrained passes described below.
85 AnalysisResolver *Resolver; // Used to resolve analysis
88 void operator=(const Pass&); // DO NOT IMPLEMENT
89 Pass(const Pass &); // DO NOT IMPLEMENT
92 explicit Pass(PassKind K, intptr_t pid) : Resolver(0), PassID(pid), Kind(K) {
93 assert(pid && "pid cannot be 0");
95 explicit Pass(PassKind K, const void *pid)
96 : Resolver(0), PassID((intptr_t)pid), Kind(K) {
97 assert(pid && "pid cannot be 0");
102 PassKind getPassKind() const { return Kind; }
104 /// getPassName - Return a nice clean name for a pass. This usually
105 /// implemented in terms of the name that is registered by one of the
106 /// Registration templates, but can be overloaded directly.
108 virtual const char *getPassName() const;
110 /// getPassInfo - Return the PassInfo data structure that corresponds to this
111 /// pass... If the pass has not been registered, this will return null.
113 const PassInfo *getPassInfo() const;
115 /// print - Print out the internal state of the pass. This is called by
116 /// Analyze to print out the contents of an analysis. Otherwise it is not
117 /// necessary to implement this method. Beware that the module pointer MAY be
118 /// null. This automatically forwards to a virtual function that does not
119 /// provide the Module* in case the analysis doesn't need it it can just be
122 virtual void print(raw_ostream &O, const Module *M) const;
123 void dump() const; // dump - Print to stderr.
125 /// createPrinterPass - Get a Pass appropriate to print the IR this
126 /// pass operates one (Module, Function or MachineFunction).
127 virtual Pass *createPrinterPass(raw_ostream &O,
128 const std::string &Banner) const = 0;
130 /// Each pass is responsible for assigning a pass manager to itself.
131 /// PMS is the stack of available pass manager.
132 virtual void assignPassManager(PMStack &,
133 PassManagerType = PMT_Unknown) {}
134 /// Check if available pass managers are suitable for this pass or not.
135 virtual void preparePassManager(PMStack &);
137 /// Return what kind of Pass Manager can manage this pass.
138 virtual PassManagerType getPotentialPassManagerType() const;
140 // Access AnalysisResolver
141 inline void setResolver(AnalysisResolver *AR) {
142 assert(!Resolver && "Resolver is already set");
145 inline AnalysisResolver *getResolver() {
149 /// getAnalysisUsage - This function should be overriden by passes that need
150 /// analysis information to do their job. If a pass specifies that it uses a
151 /// particular analysis result to this function, it can then use the
152 /// getAnalysis<AnalysisType>() function, below.
154 virtual void getAnalysisUsage(AnalysisUsage &) const;
156 /// releaseMemory() - This member can be implemented by a pass if it wants to
157 /// be able to release its memory when it is no longer needed. The default
158 /// behavior of passes is to hold onto memory for the entire duration of their
159 /// lifetime (which is the entire compile time). For pipelined passes, this
160 /// is not a big deal because that memory gets recycled every time the pass is
161 /// invoked on another program unit. For IP passes, it is more important to
162 /// free memory when it is unused.
164 /// Optionally implement this function to release pass memory when it is no
167 virtual void releaseMemory();
169 /// getAdjustedAnalysisPointer - This method is used when a pass implements
170 /// an analysis interface through multiple inheritance. If needed, it should
171 /// override this to adjust the this pointer as needed for the specified pass
173 virtual void *getAdjustedAnalysisPointer(const PassInfo *) {
176 virtual ImmutablePass *getAsImmutablePass() { return 0; }
177 virtual PMDataManager *getAsPMDataManager() { return 0; }
179 /// verifyAnalysis() - This member can be implemented by a analysis pass to
180 /// check state of analysis information.
181 virtual void verifyAnalysis() const;
183 // dumpPassStructure - Implement the -debug-passes=PassStructure option
184 virtual void dumpPassStructure(unsigned Offset = 0);
186 template<typename AnalysisClass>
187 static const PassInfo *getClassPassInfo() {
188 return lookupPassInfo(intptr_t(&AnalysisClass::ID));
191 // lookupPassInfo - Return the pass info object for the specified pass class,
192 // or null if it is not known.
193 static const PassInfo *lookupPassInfo(intptr_t TI);
195 // lookupPassInfo - Return the pass info object for the pass with the given
196 // argument string, or null if it is not known.
197 static const PassInfo *lookupPassInfo(StringRef Arg);
199 /// getAnalysisIfAvailable<AnalysisType>() - Subclasses use this function to
200 /// get analysis information that might be around, for example to update it.
201 /// This is different than getAnalysis in that it can fail (if the analysis
202 /// results haven't been computed), so should only be used if you can handle
203 /// the case when the analysis is not available. This method is often used by
204 /// transformation APIs to update analysis results for a pass automatically as
205 /// the transform is performed.
207 template<typename AnalysisType> AnalysisType *
208 getAnalysisIfAvailable() const; // Defined in PassAnalysisSupport.h
210 /// mustPreserveAnalysisID - This method serves the same function as
211 /// getAnalysisIfAvailable, but works if you just have an AnalysisID. This
212 /// obviously cannot give you a properly typed instance of the class if you
213 /// don't have the class name available (use getAnalysisIfAvailable if you
214 /// do), but it can tell you if you need to preserve the pass at least.
216 bool mustPreserveAnalysisID(const PassInfo *AnalysisID) const;
218 /// getAnalysis<AnalysisType>() - This function is used by subclasses to get
219 /// to the analysis information that they claim to use by overriding the
220 /// getAnalysisUsage function.
222 template<typename AnalysisType>
223 AnalysisType &getAnalysis() const; // Defined in PassAnalysisSupport.h
225 template<typename AnalysisType>
226 AnalysisType &getAnalysis(Function &F); // Defined in PassAnalysisSupport.h
228 template<typename AnalysisType>
229 AnalysisType &getAnalysisID(const PassInfo *PI) const;
231 template<typename AnalysisType>
232 AnalysisType &getAnalysisID(const PassInfo *PI, Function &F);
236 //===----------------------------------------------------------------------===//
237 /// ModulePass class - This class is used to implement unstructured
238 /// interprocedural optimizations and analyses. ModulePasses may do anything
239 /// they want to the program.
241 class ModulePass : public Pass {
243 /// createPrinterPass - Get a module printer pass.
244 Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const;
246 /// runOnModule - Virtual method overriden by subclasses to process the module
247 /// being operated on.
248 virtual bool runOnModule(Module &M) = 0;
250 virtual void assignPassManager(PMStack &PMS,
251 PassManagerType T = PMT_ModulePassManager);
253 /// Return what kind of Pass Manager can manage this pass.
254 virtual PassManagerType getPotentialPassManagerType() const;
256 explicit ModulePass(intptr_t pid) : Pass(PT_Module, pid) {}
257 explicit ModulePass(const void *pid) : Pass(PT_Module, pid) {}
258 // Force out-of-line virtual method.
259 virtual ~ModulePass();
263 //===----------------------------------------------------------------------===//
264 /// ImmutablePass class - This class is used to provide information that does
265 /// not need to be run. This is useful for things like target information and
266 /// "basic" versions of AnalysisGroups.
268 class ImmutablePass : public ModulePass {
270 /// initializePass - This method may be overriden by immutable passes to allow
271 /// them to perform various initialization actions they require. This is
272 /// primarily because an ImmutablePass can "require" another ImmutablePass,
273 /// and if it does, the overloaded version of initializePass may get access to
274 /// these passes with getAnalysis<>.
276 virtual void initializePass();
278 virtual ImmutablePass *getAsImmutablePass() { return this; }
280 /// ImmutablePasses are never run.
282 bool runOnModule(Module &) { return false; }
284 explicit ImmutablePass(intptr_t pid) : ModulePass(pid) {}
285 explicit ImmutablePass(const void *pid)
288 // Force out-of-line virtual method.
289 virtual ~ImmutablePass();
292 //===----------------------------------------------------------------------===//
293 /// FunctionPass class - This class is used to implement most global
294 /// optimizations. Optimizations should subclass this class if they meet the
295 /// following constraints:
297 /// 1. Optimizations are organized globally, i.e., a function at a time
298 /// 2. Optimizing a function does not cause the addition or removal of any
299 /// functions in the module
301 class FunctionPass : public Pass {
303 explicit FunctionPass(intptr_t pid) : Pass(PT_Function, pid) {}
304 explicit FunctionPass(const void *pid) : Pass(PT_Function, pid) {}
306 /// createPrinterPass - Get a function printer pass.
307 Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const;
309 /// doInitialization - Virtual method overridden by subclasses to do
310 /// any necessary per-module initialization.
312 virtual bool doInitialization(Module &);
314 /// runOnFunction - Virtual method overriden by subclasses to do the
315 /// per-function processing of the pass.
317 virtual bool runOnFunction(Function &F) = 0;
319 /// doFinalization - Virtual method overriden by subclasses to do any post
320 /// processing needed after all passes have run.
322 virtual bool doFinalization(Module &);
324 /// runOnModule - On a module, we run this pass by initializing,
325 /// ronOnFunction'ing once for every function in the module, then by
328 virtual bool runOnModule(Module &M);
330 /// run - On a function, we simply initialize, run the function, then
333 bool run(Function &F);
335 virtual void assignPassManager(PMStack &PMS,
336 PassManagerType T = PMT_FunctionPassManager);
338 /// Return what kind of Pass Manager can manage this pass.
339 virtual PassManagerType getPotentialPassManagerType() const;
344 //===----------------------------------------------------------------------===//
345 /// BasicBlockPass class - This class is used to implement most local
346 /// optimizations. Optimizations should subclass this class if they
347 /// meet the following constraints:
348 /// 1. Optimizations are local, operating on either a basic block or
349 /// instruction at a time.
350 /// 2. Optimizations do not modify the CFG of the contained function, or any
351 /// other basic block in the function.
352 /// 3. Optimizations conform to all of the constraints of FunctionPasses.
354 class BasicBlockPass : public Pass {
356 explicit BasicBlockPass(intptr_t pid) : Pass(PT_BasicBlock, pid) {}
357 explicit BasicBlockPass(const void *pid) : Pass(PT_BasicBlock, pid) {}
359 /// createPrinterPass - Get a function printer pass.
360 Pass *createPrinterPass(raw_ostream &O, const std::string &Banner) const;
362 /// doInitialization - Virtual method overridden by subclasses to do
363 /// any necessary per-module initialization.
365 virtual bool doInitialization(Module &);
367 /// doInitialization - Virtual method overridden by BasicBlockPass subclasses
368 /// to do any necessary per-function initialization.
370 virtual bool doInitialization(Function &);
372 /// runOnBasicBlock - Virtual method overriden by subclasses to do the
373 /// per-basicblock processing of the pass.
375 virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
377 /// doFinalization - Virtual method overriden by BasicBlockPass subclasses to
378 /// do any post processing needed after all passes have run.
380 virtual bool doFinalization(Function &);
382 /// doFinalization - Virtual method overriden by subclasses to do any post
383 /// processing needed after all passes have run.
385 virtual bool doFinalization(Module &);
388 // To run this pass on a function, we simply call runOnBasicBlock once for
391 bool runOnFunction(Function &F);
393 virtual void assignPassManager(PMStack &PMS,
394 PassManagerType T = PMT_BasicBlockPassManager);
396 /// Return what kind of Pass Manager can manage this pass.
397 virtual PassManagerType getPotentialPassManagerType() const;
400 /// If the user specifies the -time-passes argument on an LLVM tool command line
401 /// then the value of this boolean will be true, otherwise false.
402 /// @brief This is the storage for the -time-passes option.
403 extern bool TimePassesIsEnabled;
405 } // End llvm namespace
407 // Include support files that contain important APIs commonly used by Passes,
408 // but that we want to separate out to make it easier to read the header files.
410 #include "llvm/PassSupport.h"
411 #include "llvm/PassAnalysisSupport.h"